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ICAL INSTRUCTION IN 
A FASCINATING ART 




FIFTY CENTS 



POPULAR MECHANICS HANDBOOKS 




UNIVERSITY OF CALIFORNIA 
AT LOS ANGELES 




UMVERSriTofCALIFORNM 

AT 

LOS ANGELES 
LIBRARY 



Metal Spinning 

BY 

Prof. FRED D. CRAWSHAW, M. E., 

Assistant Dean, 
College of Engineering, University of Illino'u 



POPULAR MECHANICS HANDBOOKS 



CHICAGO 
POPULAR MECHANICS CO. 



Copyrighted, 1909, 
By H. H. WINDSOR 



1 

^0 (e 



THIS book is one of the series of 
handbooks on industrial subjects 
being published by the Popular 
Mechanics Co. Like the magazine, these 
books are "written so you can under- 
stand it," and are intended to furnish 
information on mechanical subjects at a 
price within the reach of all. 

The texts and illustrations have been 
prepared expressly for this Handbook 
Series, by experts; are up-to-date, and 
have been revised by the editor of Pop- 
ular Mechanics. 




Fig. 1 Lathe for Metal Spinning 



Chapters 

The Lathe and Its Parts . . Chapter I 

Tools Chapter II 

The Preparation of Metal for Spinning 

' Chapter III 

How to Spin a Hollow Dish . Chapter IV 

How to Spin a Deep Dish . Chapter V 

How to Spin a Vase . . . Chapter VI 
How to Spin Some Unclassified Forms 

Chapter VII 



METAL SPINNING 



INTRODUCTION 

Sheet metal, which is' now pressed and stamped into a great va- 
riety of forms for commercial uses, was, up to a few years ago, either 
hammered or spun into the desired shapes by a comparatively 
few artisans who had learned the art of cold-metal working in 
Europe. Like so many other of the old-time crafts, the one of 
metal spinning has partially come into disuse because of commer- 
cial competition and the failure of the younger generation of men 
to familiarize themselves with the handwork of their fathers. In 
the United States, it is only in the larger cities that one occa- 
sionally finds an artisan who does metal spinning; when such a 
person is found, he is usually occupied in producing forms out 
of thin metal that require great care in making or are difficult 
to produce with a stamp or press. Sometimes, however, where 
only a comparatively few articles of any particular shape are 
desired, they are spun instead of stamped out, to save the cost 
of dies. 

It is believed in some quarters, particularly among metal 
spinners, that pressing and stamping metal can never fully take 
the place of spinning it. It is impossible to press or stamp some 
forms except as they are produced in parts and these parts sol- 
dered, brazed or riveted together. This is manifestly undesir- 
able for many kinds of work. 



10 METAL SPINNING 

The fact that modern commercial tendencies are in the direc- 
tion of abolishing metal spinning wherever possible does not 
mean that large sheet-metal working establishments do not em- 
ploy metal spinners; it does mean, however, that these men are 
called upon to do the hardest kind of spinning without much 
possibility of learning how to do the simpler forms of this work. 

It is for the double purpose, therefore, of making it possible 
for amateurs to be helped in me\a spinning and to renew this 
craft where metal spinning is really more serviceable than its 
substitutes, that this book is written. 

From the standpoint of the craftsman, metal spinning is a 
craft which is highly desirable of attainment and which may 
replace beaten-metal work in some cases, or, in many cases be 
used in connection with it. The principal field of the metal 
spinner, however, is the production of forms for plated ware. 
Practically all silver plate has white metal, which has been pressed 
or spun into shape, as a base. There are also many forms used 
in connection with manufactured articles, notably electric fix- 
tures, which can be, and many times are, spun with greater 
certainty of good results than could be possible if other methods 
are used. 

For those who take up this work for the first time, it is sug- 
gested that forms be undertaken after the order of those de- 
scribed in the following chapters and that copper well annealed 
be used as the practice metal. 

FRED D. CRAWSHAW 



CHAPTER I 

THE LATHE AND ITS PARTS 

Metal spinning does not take a particularly prom- 
inent place among the trades in the United States. 
Inasmuch as it is perfectly possible to spin metal on 
an engine lathe or a speed lathe, if either is properly 
equipped for this work, few manufacturers of ma- 
chine tools make a lathe specially for spinning. 
The work requires a lathe which will not move side- 
wise to any great extent as a result of heavy work 
running at a high speed. The ordinary engine lathe 
does not fulfil the requirements of speed; on the 
other hand the speed lathe, unless it is designed for 
heavy work, is liable to be unstable. 

The frontispiece, Fig. 1, illustrates a strong 
speed lathe equipped for metal spinning. It will be 
noticed that the legs of the lathe are particularly 
well braced and that the entire machine presents 
the appearance of strength. Inasmuch as the writer 
has worked upon a lathe similar to the one illus- 
trated and has spun different kinds of metal of vary- 
ing disk diameters on it without inconvenience 
from lathe vibration, he feels that he can safely 
recommend a strong speed lathe for ordinary metal 
spinning work. 

The principal lathe requirement for good spin- 
ning is a speed ranging from 1,800 r.p.m. to 2,500 
r.p.m., which can be maintained with but slight 
variation whether light or heavy spinning is being 
done. The length of the spinning tools and the 
method of holding them produce a firm contact be- 



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METAL SPINNING 




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METAL SPINNING 13 

tween the tool and the metal, and this requires a 
lathe which has in store a considerable amount of 
reserve power. For ordinary work, a spinner 
should use at least a half-horsepower lathe, but for 
work in schools or light work in shops, good results 
can be obtained with a quarter-horsepower lathe 
which has a large head cone and is strongly belted. 

The parts of the lathe, when equipped for metal 
spinning, which differ from corresponding parts 
when the lathe is used for metal turning, are the 
headstock, faceplate, tool-rest and tail center. The 
dog which is so commonly used in the metal work- 
ing shop to hold work from slipping in the lathe as 
it revolves is never used in metal spinning. The 
ordinary center screw faceplate or outside screw 
faceplate used in wood-turning is screwed onto the 
headstock spindle. Upon the faceplate is screwed 
a block of hard wood, usually hard maple ; this is 
turned with wood-turning tools to the shape de- 
sired for the first form in the process of spinning. 
The circular disk of metal which is to be spun is 
centrally placed against this turned form and held 
in place by the tail center which is brought in con- 
tact with it. Prior to the time when spinning be- 
gins, the circular disk of metal is held in place by 
friction between the wooden form fastened to the 
faceplate, over which the metal is to be spun, and the 
tail center. The process of spinning will be de- 
scribed later. 

The lathe rest commonly used is shown in Fig. 2. 
A and B are both pieces of wrought iron which 
have been fastened together by turning a shoulder 
on the upper end of B and fitting the part thus made 
into a hole bored in the middle of A and counter- 



14 



METAL SPINNING 




METAL SPINNING 15 

sunk at the top. The two pieces are securely fas- 
tened together by riveting the end of B into the 
countersunk part of A. This simple "T"-rest is 
fastened into the slide-rest of the lathe. It replaces 
the tool-rest in the wood lathe equipment. Now, 
as will be explained in a succeeding chapter, the 
plying of the tool over the disk of metal, to press 
it securely over the turned form, requires the 
spinning tool to act as a lever. The direction 
of motion of the lever varies from a vertical plane 
at the beginning of operations to a horizontal plane 
at the completion of the spinning process. In order 
that this may be done without the tool slipping on 
the rest, vertical holes are bored about % in. to 1 in. 
apart in the horizontal portion of the rest in which 
is inserted a movable pin. The position of the tool 
on the rest is shown in the illustration, Fig. 3. As 
the metal is gradually pressed over the form the 
pin is moved toward the headstock of the lathe by 
changing it from one hole to another. For small 
work the horizontal portion of the "T"-rest can be 
made out of %-in. or %-in. square stock. A %-in. 
rod will answer the purpose for the rest-pin. The 
pin should be shouldered squarely at the bottom to 
fit into Vt-in. holes bored in the rest. 

The size of the vertical portion of the "T"-rest 
will depend upon the hole in the slide-rest which 
receives it. I am assuming, in this description, that 
an ordinary speed lathe is remodeled to serve for 
spinning purposes. Some difficulty may be found 
in the rest slipping when considerable pressure is 
used in the spinning process. This might be 
avoided by using a "T" or square pin joint to fasten 



16 



METAL SPINNING 




METAL SPINNING 17 

the two parts of the rest together. However, if the 
operator will shift the lathe carriage from time to 
time to keep the fulcrum point as nearly as possible 
over the central portion of the rest, little difficulty 
will be experienced in this direction. 

In describing the spinner's center I shall illus- 
trate and refer to three. All of these are shown in 
Fig. 4. The one at the top is to be found in the 
market. The one in the center of the illustration 
is described because a practical spinner, after years 
of experience and after using many forms of 
centers, finally concluded that this one filled all re- 
quirements better than any other he had ever seen 
or used. 

Two things are absolutely necessary in any cen- 
ter w r hich is used in metal spinning. The first : light 
contact must be kept between the end of the 
center and the surface of the metal being spun. In 
other words, there must be absolutely no slipping 
at this point. The second : this portion of the 
center which sticks, as it were, to the spinning 
metal should move freely and without much, if any, 
wear on the remainder of the center which is in- 
serted in the tailstock. In order to have these two 
essential factors present in spinners' centers many 
devices have been constructed. Different spinners 
use different centers, often devices of their own ; 
but experience has shown that the two centers here 
described have worked well I do not say perfectly. 
The center illustrated at the bottom of Fig. 4 is one 
which the writer tried as a result of some trouble 
which he had with the top center shown in Fig. 4, 
and before he used the one shown in the center of 



18 METAL SPINNING 

this illustration. It has the advantage of having 
but one moving metal part, which serves a good pur- 
pose in some respects, viz, it reduces to a mini- 
mum the trouble due to many parts. On the whole, 
the middle center shown in Fig. 4 proves the most 
satisfactory. 

The stock center is made in three parts A, B and 
C. A and C are cast-iron parts and B is a washer 
made of some hard substance such as hard rubber 
or vulcanized fiber, against which cast-iron' will run 
freely. B is supposed to fit tightly upon the pin of 
C so that A alone revolves when the center is firmly 
pressed against the disk of mecal to be spun. A 
may be made in different shapes to accommodate 
different forms and sizes in spinning and should be 
lubricated by occasionally dropping oil upon the pin 
of C. This pin should not enter A farther than is 
necessary to form a good bearing, and should fit 
about as tightly in A as a shaft in a high-grade ma- 
chine fits in its bearing. The one difficulty which 
the writer has had with this center, as well as with 
the second center described, is the impossibility of 
making the diameter of A small enough for some 
work. This may not be considered an objection in 
the trade work, but in schools, where small pieces 
will naturally be spun more than large ones, it 
sometimes forms a serious drawback to accomplish- 
ing good results. The center shown at the bottom 
of Fig. 4 was found to overcome this difficulty be- 
cause the revolving part of the center can be turned 
as small as one desires. Here, however, it should 
be mentioned that, if the end bearing surface in con- 
tact with the work is made too small, a perfect 



METAL SPINNING 19 

contact between the tail center and the work cannot 
be secured and a very undesirable slipping- will 
occur. It is true, nevertheless, that small work re- 
quires slight pressure from the tool, and, as a result, 
less pressure from the center than is required in 
large work. A small center, then, for small work 
is as serviceable, comparatively, as a large center 
is for large work. 

The center illustrated in the middle of Fig. 4 has 
three parts as does the stock center, but two of 
them, A and B, are movable, or supposedly so; 
whereas, in the first center described, only one part, 

A, is supposed to revolve. A is a piece of wood ; B 
is made of wrought iron or steel; C is preferably 
made of the same material as B. It has been stated 
that both A and B are supposed to revolve. Such 
revolution is not necessary, however. If A revolves 
upon B, the necessary requirements are fulfilled ; 
or, if A and B together revolve, the same results 
are obtained ; likewise if A revolves slightly upon 

B, and B revolves slowly in C, the same result is ob- 
tained. Herein lies one supposed or imaginary 
advantage which this center has over the stock 
center, viz, that if one part, A, sticks upon another, 
B, similarly if B sticks in C there still remains the 
possibility of a perfect bearing at a second point. 
While this is undoubtedly true, there is always the 
possibility of both A and B sticking, and as this 
center has more parts than the others, there is more 
danger of its getting out of order. Furthermore, as 
A is made of wood, it will burn as it revolves upon 
B, unless the movement between A and B is slight, 
or A is well lubricated upon B. Of course, it is an 



20 METAL SPINNING 

easy matter to duplicate A, and it may be said here 
that it is well to have a number of this part of the 
center in stock. A broom handle, sawed into one- 
inch lengths with the proper hole drilled at the 
center of each sawed-off part, will provide pieces 
for a considerable length of time. 

There is an idea among some spinners that the 
part coming in contact with the metal to be spun 
should be made of wood so that a better "stick" may 
be secured than is possible with a metal end. 
Whether this is a fact or not, however, must be de- 
cided by each workman. It is sometimes found 
advantageous to put a little resin on the end of the 
center in order to increase the friction between it 
and the metal to be spun. Again, when the part A 
is made of wood, it is possible to drive into the end 
next to the work a few small brads. These may be 
left extending from the center-end just enough to 
catch on the disk as it revolves in the spinning 
process. 

Any one of the three centers described work well, 
but, as has been intimated, not at all times per- 
fectly. I believe there is an opportunity for some- 
one to devise a more perfect spinning center. I have 
wondered if some ball bearing center might not 
solve the present difficulties. Such a center is illus- 
trated in Fig. 4. It has been used with success in 
school work according to the statement of the in- 
dividual who devised it. 



CHAPTER II 
TOOLS 

The tools used by metal spinners are difficult to 
name. Very few spinning operations require the 
use of any one particular tool. This fact contributes 
to the present condition regarding metal spinning 
tools in general, viz : They are usually not to be 
found in stock and, when found, the forms used for 
the different processes vary considerably in differ- 
ent sections of the country. There are a few stand- 
ard forms, however, and while it is true that old 
spinners usually make their own tools, they con- 
form to regular practice in making these few stand- 
ard forms. 

The tools commonly spoken of by the machinist 
as the hand-tool diamond point and the cut-off tool 
are the only edge tools used in metal spinning ; 
consequently, there is little danger of the operator 
being cut while spinning metal. To aid further in 
eliminating the factor of danger in the use of tools, 
nearly all spinning tools, except the above-men- 
tioned two, may be used with the end of the tool 
placed under the work. In most lathe processes the 
tools are pushed into a revolving piece or placed on 
top of it as is the case in some kinds of wood turn- 
ing. This feature of comparative safety is one 
which recommends itself to many who contemplate 
starting metal spinning in schools. 

Because all spinning tools are used by pressing 
their ends against the work, considerable friction 



22 METAL SPINNING 

results, and to minimize this as much as possible, 
the tools in a spinner's kit, except those mentioned 
for cutting and trimming (the diamond point and 
cutting-off tools), should be ground perfectly 
smooth and then well polished with emery. 

I have said it is difficult to find spinners' tools 
kept in stock. Perhaps this is the reason why their 
names are not well known. In talking with an old 
spinner concerning the names of the tools in his set, 
he said, "Why sir, I have been a spinner for thirty 
years in Sweden and in the United States and it 
seems as though I had always known how to use 
every tool on this shelf, but I cannot give you the 
name of one of them. As a boy I was carefully 
taught how, why and where to use each one but I 
always heard them called 'this tool' or 'that tool.' 
I don't believe they have any names." I suggested 
that no one ought to be better prepared to name 
spinners' tools than he after his life's experience and 
so, with some persuasion, he suggested the names 
which I shall use in connection with the tools de- 
scribed and illustrated in the next few pages. Some 
were named because of their shape, and for others 
names were suggested by the kind of work which 
they performed. 

In the average set of tools in an expert spinner's 
set will be found from one to two dozen forms. 
Perhaps not more than six or eight tools are in or- 
dinary use. As it is with most specialists, the 
individual metal spinner will collect a number of 
forms which he will use only once in a great while. 
I shall make reference to only six of the more im- 
portant tools here, and I venture to say from some 



METAL SPINNING 23 

experience that any spinning except that which 
may be designated as "special" can be done with a 
part or all of these. 

The round-nose, Fig. 5, is made of %-in. round, 
hexagonal or octagonal steel. Round stock, for the 
work which this tool does, is probably the best. It 
is forged into the desired shape and at least 3 in. of 
the end carefully ground ; probably one-half or more 
of this distance ought to be polished. The kind of 
work to be done, and the peculiar tastes of the 
workman can alone determine the exact shape most 
suitable for this or other tools. For this reason two 
or three round-nose tools, varying in form from the 
long to the short pointed, may be used to advan- 
tage. The extreme end must not be a sharp point 
in any case for fear of its catching the revolving 
metal and tearing it. It is advisable, however, in 
order to press the tool into small grooves, to have 
the end as pointed as possible and yet have it 
slightly rounded. 

The round-nose is used to a greater or less degree 
according to the regularity of form in the object 
being spun, but, in general, it is used to the exclu- 
sion of all others in starting to spin a piece, and by 
many workmen it is used more than any other one 
tool. It is especially useful in compressing metal 
into cavities and in pressing out any irregularities 
or wrinkles before removing work from the lathe. 

The tool which is probably as difficult of con- 
struction as any is shown in Fig. 6 and, for lack of 
a better name, will be called the raising-up tool. 
As this tool is used in operations which require 
considerable force applied by the workman, and, 



24 



METAL SPINNING 




V 



c 



METAL SPINNING 25 

also, because in forging the tool a neck is formed 
smaller than the regular stock, it is well to use steel 
a trifle larger than that used for the round-nose. 
Where ^-in. stock is used for the tool just de- 
scribed, %-in. or even %-in. material can profitably 
be used in the construction of the one now under 
discussion. Hexagonal or octagonal steel is gener- 
ally considered more desirable for the raising-up 
tool than round stock. The forging of this tool 
must be done with a great deal of care. The first 
process is to upset the end of the tool. The second 
process is to draw down the neck, leaving a knob 
of metal on the end which is sufficient in size to 
form the finished end. There is one danger against 
which the forger must constantly guard in upset- 
ting and hammering the tool into shape. I refer to 
the leafing or lapping of metal which, unless a weld- 
ing heat is reached, will leave seams in the finished 
tool that will make it almost useless. Again, in 
tempering, great care must be taken not to produce 
a crack in the neck just back of the head. The use 
to which the raising-up tool is principally put 
that of forming concave bottoms on dish forms or 
operations which require surfaces to be spun con- 
cave instead of convex toward the headstock 
makes it necessary that the head of this tool should 
have a lobe left at the point lettered A, Fig. 6, in 
order that the tool can hook under the metal and 
draw it up into an undercut groove. 

I have endeavored to make the drawings of these 
tools as nearly correct as possible according to the 
suggestions which I have received from spinners 
and from my own experience, and in the case of this 



26 



METAL SPINNING 




METAL SPINNING .27 

particular tool the form as illustrated has been 
made with special care. It should be noticed that 
the surfaces CD and EF are slightly convex out- 
ward. 

The planisher is the name given to the tool con- 
sidered third in importance. Hexagonal %-in. steel 
is used to make it and is hammered into the form 
shown in Fig. 7. All that portion of the steel which 
has been changed in shape by forging the tool 
should be ground and polished. Especially, should 
care be taken to have the two flat tapering surfaces 
true and perfectly smooth. It is quite important, 
also, that the end should be straight with reference 
to the width of tool and neatly rounded with refer- 
ence to the thickness. The principal use to which this 
tool is put is that of a burnisher. It is used, there- 
fore, almost entirely as a finishing tool. The flat 
surfaces are placed against cylindrical or conical 
surfaces and the end is used in perfecting small 
grooves by pushing it into the concavity as one 
would push a cutting-off tool into a piece of spindle 
wood turning. 

So far we have spoken of tools which seem to 
have been designed to make concave surfaces, prin- 
cipally, such as large or small grooves or cup- 
shaped formations. The tongue tool shown in Fig. 
8 has its principal use in forming convex surfaces, 
or ? as the spinners sometimes say, in "turning over" 
the metal. It is usually made from stock as small 
or smaller than that used in the construction of the 
other tools described. The planisher is used in its 
stead when large convex surfaces are spun. It is 
not necessary that the tongue should be forged. If 



28 



METAL SPINNING 




METAL SPINNING 29 

care is taken, the flat surface can be ground without 
burning the steel. This flat surface is the part of the 
tool which is used principally ; the one operation of 
grinding together with polishing puts it in condi- 
tion. It is well to have the cylindrical part of the 
tool, opposite the flat surface, ground and polished. 
This surface can sometimes be used. 

It is believed that the tools of which mention has 
already been made might conclude the list of those 
making up the necessary tools in a spinner's kit. if 
it were not for some extraordinary or unusual 
shapes in spun work. For the purpose of spinning 
these peculiar forms special tools may be made at 
any time. 

There are two other tools, the groover and the 
knob-raising tool illustrated in Figs. 8 and 9 re- 
spectively which may be used in places as substi- 
tutes for those already described, with perhaps 
some additional ease. 

The groover, as the name implies, is used in mak- 
ing grooves. The operator finds the use for this 
tool almost entirely in spindle forms and, then, only 
for small grooves. It will be noticed from the cross- 
sectional view shown that small grooves of varying 
sizes may be made by simply using the tool in con- 
tact with the metal at different points on the curve 
of the tool. It is placed on top of the lathe-rest with 
the end hanging down and on the lathe side of the 
rest. The operator presses down on the handle, 
thus making a lever of the tool with the rest as the 
fulcrum. 

As will be discerned later, the knob-raiser may be 
used in raising up or hooking under the metal in 



30 METAL SPINNING 

spinning a dish concave toward the headstock; or 
it may be used by pressing it endwise toward the 
line of centers on the lathe, to form a concavity on 
a spindle form. It should be a comparatively easy 
matter to forge the knob-raiser, inasmuch as the 
end is simply upset in the fire and afterwards 
ground into the desired shape and polished. 

Figure 10 gives the shape and the dimensions of 
the accepted handle for spinning tools. In this 
figure, also, is represented the method used in fas- 
tening the tool into the handle. Probably the best 
wood out of which handles may be turned is 
straight-grained, hard maple. 

It is necessary that all tools, except those used 
for cutting and trimming purposes, should be long 
enough to permit the end of the handle to rest under 
the arm and thus aid the workman in getting a 
strong leverage by throwing the weight of his body 
downward. The handles are usually made from 12 
to 15 in. in length and the tool long enough to admit 
of its being driven into the handle from 4 to 5 in. 
Pieces of gas or water pipe make very good ferrules. 
The tool and handle when fastened together should 
be from 2 ft. to 30 in. in length. Inasmuch as the 
tools are highly tempered, the wearing due to the 
spinning process does not change their shape rap- 
idly. Consequently, reforging is not necessary 
except after the tool has been in service for a con- 
siderable length of time. 



CHAPTER III 

THE PREPARATION OF METAL FOR 
SPINNING 

The metals commonly used in spinning are cop- 
per, white metal, brass, zinc and aluminum. Metals 
must be used which, by some process such as an- 
nealing, can be made perfectly pliable. It must be 
evident that only when metal is perfectly pliable 
can it be spun over irregular shapes. The constant 
friction between the tool and the metal tends to 
harden the metal, and hence it must be softened 
and made pliable, many times it may be, during a 
spinning process. 

The thickness of metal most suitable for ordinary 
work varies from Brown and Sharpe gage No. 22 
to No. 26, inclusive. Metal gaging 22 is used for 
the largest work only and then principally when 
the metal is copper. Gage 24 in brass and zinc be- 
comes pliable with proper treatment and can be 
successfully used for forms varying in diameter and 
height from 3 in. up to 5 or 6 in. Metal of B. and 
S. gage No. 26 is more easily spun than thicker 
material, due to the fact that it assumes easily and 
quickly the desired form. Because of this fact, 
however, articles spun from it are sooner ruined 
than those spun from thicker metal. Gage 26 will 
not stand the continual pressure of the spinning 
tool very long. Metal of No. 26 gage is naturally 
adapted to the smallest work, but to be successfully 
spun should be used by workmen of some experi- 
ence. 



32 METAL SPINNING 

Thus far we have spoken of metals in a general 
way, and of no one metal in particular. We will dis- 
cuss briefly the preparation and best uses of the four 
metals mentioned above. 

Copper 

Copper, varying in thickness between the gages 
referred to above, is perhaps most suitable for all 
general spinning, especially for school work and for 
amateurs. It is tough and when heated is very 
pliable. It is not so easily shattered by overheat- 
ing, numerous heatings or long continuous working 
as are the other metals mentioned. It should be 
understood that all operations, in preparing the 
metal for spinning and those used after spinning is 
begun, should be as brief as possible and never 
duplicated unless necessary. As a matter of fact 
the annealing process will be repeated many times 
of necessity, especially by beginners. In learning 
to spin, one will keep the tool in one place on the 
metal until it becomes hard and tempered in a 
sense. As a young spinner will probably find diffi- 
culty in successfully producing a desired form in 
one operation it will be necessary for him to anneal 
or soften the copper before he completes spinning. 

One must first calculate, with some degree of pre- 
cision, the size of circular disc necessary to form the 
spun article. If spinning is properly done, the 
metal will be thinned very little, if any, in working 
it; consequently the computation of the disc size 
will involve in most cases some mensuration, but, 
principally, a good supply of common sense and 
judgment is needed. The workman will be greatly 
aided in his computation if he will make a cross- 



METAL SPINNING 33 

sectioned drawing (through the axis of revolution) 
of the object he is spinning, and, with a pair of divid- 
ers, set to a small span, step off the length of the 
outline desired. Thus if in B, Fig. 11, (Cup and 
Chucks) one should start at O and step carefully 
by 1 and 2 to 3 he would have the radius of the disc 
out of which the cup could be spun. It will be de- 
sirable to make the radius of the disc slightly 
greater than the distance thus determined, if the 
metal is to be compressed any. If, on the other 
hand, the metal is thinned due to unnecessarily 
working the tool over the metal, the radius need not 
be quite as large as the outline distance spoken of. 

The disc after being cut from a large sheet in 
which form the metal is best purchased is heated 
in an annealing furnace or over a Bunsen burner 
until it changes to an iridescent color and a film of 
copper oxide burns off. If an annealing furnace is 
used, the temperature may be controlled ; but in 
case a Bunsen burner or blow-lamp is used one of 
which methods would be followed probably for 
small work the coloring of the metal, when the 
proper temperature is reached, must be the means 
of determining when the copper has been heated 
sufficiently. If it is heated beyond the proper point 
the strength of the metal is weakened and it may be 
even exhausted entirely. Nevertheless, in rough 
work, copper is heated until it is "red" hot and im- 
mediately plunged in water. This constitutes the 
annealing process. Some spinners, especially 
where considerable care is taken to preserve the 
strength of the metal, cover copper with oil when 
annealing it. This is by no means an undesirable 



34 



METAL SPINNING 




METAL SPINNING 35 

plan. The film of oil will evaporate and burn off as 
heat is applied ; when the oil has completely disap- 
peared the metal should be annealed. This, as well 
as the first method described, will not necessarily 
give accurate results. Both methods are simple, 
practical means which, together with a little experi- 
ence, will aid in reaching uniform results. 

If very precise work is necessary, as, for example, 
in spinning some article which must be kept under 
intense pressure, the best temperature for anneal- 
ing must be carefully ascertained by experiment. 
In this case the annealing or some similar furnace 
should be used where accurate temperatures can be 
recorded. 

To make this description perfectly clear it may 
be said that the. following steps should be taken in 
spinning a piece of copper. 

First : Cut from a plate of soft copper a circular 
disc of a calculated size to spin from it a particular 
object. 

Second : If the copper is not quite soft and 
pliable heat it to a red heat and immediately plunge 
it into cold water. 

Third : Place the disc in the lathe ready to spin. 
Apply the tool to it until the copper begins to 
harden perceptibly. 

Fourth : Remove the copper from the lathe and 
anneal as previously described. 

Fifth: Repeat the above instructions in the 
order given as few times as possible, but until the 
spinning process is completed. 

White Metal 
White metal is very easily spun and does not 



36 METAL SPINNING 

need to be annealed. In the trades it is used as the 
base for most silver-plated ware ; and consequently 
for forms which cannot be pressed out, the spinning 
process is a necessary one. If the lightness of the 
plated piece has not a large consideration in its 
production, it is advisable to use quite heavy white 
metal. There will be an explanation made in a 
future chapter concerning the drawing-out of metal 
in spinning. As the spinning process continues, the 
metal is liable to be worked thin by being drawn 
out. This is especially true in the case of white 
metal and thus the suggestion with reference to the 
use of heavy metal is opportune. 

Brass 

Brass is prepared for spinning in the manner de- 
scribing the annealing of copper. The change of 
color in brass is not so perceptible, when sufficient 
heat has been applied, as in copper, and conse- 
quently the method of covering the metal with oil 
before heating will probably be the safest in anneal- 
ing brass. For ordinary spinning it is quite imma- 
terial whether or not one applies the same amount 
of heat for each annealing, so long as the metal is 
not overheated. Brass hardens more rapidly 
through the use of the spinning tool than copper 
does. When we remember, then, that there is 
greater danger of spoiling the metal by annealing 
it many times than by slightly overheating it once, 
we will understand why brass is more difficult to 
spin than copper. Wherever possible, one should 
use as thin brass as will be consistent with the 
strength required. 



METAL SPINNING 37 

Zinc 

We have said that it was perhaps advisable to im- 
merse copper and brass in oil before annealing. 
This is still more important with zinc. Whether it 
is necessary or not to oil or grease zinc while heat- 
ing it may be a question, but it is certainly advisable 
in the minds of old spinners. The theory seems to 
be that the oil tends to soften the metal when heat is 
applied. Zinc has a decidedly crystalline formation 
and the friction caused by the spinning tool rubbing 
against it tends to make it more, rather than less, 
crystalline. This molecular condition weakens the 
metal by decreasing its tensile strength and it be- 
comes decidedly difficult to spin; especially is this 
true in thick pieces which have to be turned over 
abrupt corners. The melting point for zinc is about 
780 Fahrenheit, which is considerably lower than 
the melting point for copper or good brass. This 
necessitates much more care in annealing zinc than 
is necessary with any other metal which is capable 
of being spun. It is decidedly advisable not to 
reach a temperature above 350 or 400 F. Of 
course this point in temperature cannot be deter- 
mined except in an annealing furnace. It should be 
understood that after zinc is heated as above ex- 
plained it is plunged into cold water before any 
attempt is made to spin it. 

Aluminum 

Ordinarily, aluminum does not need annealing. 
It may be better to heat it slightly when the metal 
is thick, but this is a matter which the operator 
must determine for himself by experiment. Like 
white metal, aluminum is easily worked, but it is 



38 METAL SPINNING 

also easily shattered; and consequently the ease 
with which it can be spun sometimes results in a 
spoiled piece after considerable work has been done 
on it. Aside from the point of its being a good base 
for plated ware, there is no advantage in using 
aluminum. It is, however, light, and therefore may 
be desirable to use for large spun pieces. 



CHAPTER IV 

HOW TO SPIN A SHALLOW DISH 

The very simplest spinning operations possible 
are involved in the spinning of a shallow dish of 
small diameter, such as a pin tray. Shallow forms 
may be difficult to spin, however, if they are irreg- 
ular and complicated in cross-sectional outline. 
The one thing which makes them good examples 
for amateurs is their shallowness. They should be 
simple in form, also, if they are first pieces in spin- 
ning. I should say the amount of depression should 
not exceed 1 in. and the diameter should not be 
greater than 6 in. in the spinner's initial dish. 

A shallow dish may be in either of two general 
classes, depending upon form, viz : one in which 
the curve of depression is gradual from the rim to 
the bottom ; or one in which the bottom of the dish 
is comparatively flat and the rim is formed by 
abruptly turning the metal over a corner, the rim 
being perpendicular to the general plane of the bot- 
tom. In the first class we find the saucer, and in 
the second such a form as the cover to a tin box 
a baking-can, for example. 

It will be evident that one of two things will tend 
to make a dish difficult to spin ; either its great 
depth or some sharp corner which forms the divid- 
ing line between two surfaces. Right angle corners, 
therefore, are difficult to spin ; especially so when 
the surface turned over, as in the rim of a dish, is 
very high. 



40 METAL SPINNING 







Attractive in Shape and Finish 



METAL SPINNING 41 

Either of the two faceplates sent with a wood- 
turning lathe may be used for the wooden form- 
blocks over which the metal is spun. It is best to 
use the center-screw faceplate for work of small 
diameter, such as a cup, for example; and the sur- 
face-screw faceplate for work of large diameter. If 
this suggestion is followed, one will probably use 
the surface-screw faceplate to spin low dish forms. 
The wooden form-block is made according to ac- 
cepted methods of wood-turning. Two things must 
be true if the form is to serve satisfactorily the pur- 
pose for which it was turned : It must be perfectly 
smooth and it must be hard. Hard maple, well- 
scraped and sandpapered, makes a very good form 
for most spun work. 

In some cases, as will be illustrated later, it is 
necessary to split a form in order to release it from 
the spun article. Dogwood is considered the best 
for this purpose, although straight-grained hard 
maple will answer the purpose very well. When a 
number of one particular form are to be spun, it is 
economy of time and labor to construct a cast-iron 
form-block. It is best not to loosen a form-block 
from the faceplate after it is once put in place until 
all spinning is finished. This may require the con- 
struction of duplicate faceplates for each lathe in 
case a lathe is used for some purpose besides the 
one in question before a spinning job is completed. 
It is better to do this, however, than to have the 
work running out of true due to removing the form- 
block from a faceplate to allow other work to be 
put on it. 

When the metal disc has been cut and centered 







a&. ^\^ 

%^^^^ 





Artistic Designs 



METAL SPINNING 43 

moderately well in the lathe between the spinners' 
center and the form over which it is to be spun, the 
workman is ready to begin spinning. (A cut show- 
ing the work in this stage is found on page 14.) 
It will be remembered from the discussion on spin- 
ners' centers that at first nothing holds the disc in 
a central position except the pressure of the center 
against the piece to be spun. 

It is necessary to keep metal well greased when 
spinning it. Before putting it in the lathe it is well 
to apply whatever lubricant is to be used, and dur- 
ing the spinning process to make further applica- 
tions whenever the disc becomes dry or at any time 
after it is annealed. Soft soap is considered as sat- 
isfactory as anything to use on copper. On brass 
and zinc spinners rub a tallow candle and this may 
be used, too, on copper. White metal and alumi- 
num need only a little heavy oil from time to time 
to keep the tool from grinding the metal. 

The illustration on page 14, Fig. 3, shows the 
general position of spinning tool and workman 
when the spinning process begins. In the right 
hand, with the handle under the right arm above 
the elbow, is held the spinner's tool and in the left, 
the end of a broom handle or some hard piece of 
wood of similar shape. Until it is possible to press 
the metal firmly against the form-block fastened on 
the faceplate the end of the piece of wood held in 
the left hand is kept opposite the end of the tool as 
it moves from the center of revolution outward and 
downward. The piece of metal as it is revolving 
has a piece of wood (tapered to allow a flat surface 
to come in contact with the spinning metal) on its 



44 METAL SPINNING 

left, and the spinning tool on its right. The revolu- 
tion of the lathe draws the tool down so that it is 
nearer the axis and a little lower than the end of 
the wooden support held in the left hand. The body 
throws the handle to the right, which causes the 
end of the tool to press to the left and consequently 
move the metal gradually toward and finally 
against the form-block. When the metal has at 
last been spun tightly against the form-block, the 
diamond point is used to trim the edge and the spun 
piece is complete. Usually in spinning a low dish 
of regular shape it is not necessary to anneal the 
metal after it is first put in the lathe. It should be 
understood, however, that annealing is necessary 
whenever the metal becomes hard. If it is not an- 
nealed as soon as it becomes hard it will shatter. 

The spinning process may be accomplished also 
by holding the tool as described, except to have the 
tool end above the center of the lathe instead of be- 
low it. If this position is taken, the movement of 
the body must be two-fold, viz : downward and to 
the right, which will result in the tool point work- 
ing upward instead of downward. 

Probably in spinning a simple dish form no diffi- 
culty will be experienced in keeping the metal to a 
uniform thickness and the same thickness approx- 
imately as it was in the sheet. If, however, it is 
found that the metal is thinning, the tool, by revers- 
ing the movements of the body, must be made to 
travel toward the center of revolution. This will 
compress instead of draw out the metal. It must 
be very evident that an inward movement of the 
tool point will tend to bulge the metal at the point 



METAL SPINNING 45 




Three Attractive Pieces 



46 METAL SPINNING 

where it is held between the center and the form- 
block. It is to avoid this, principally, that the first 
movement of the tool is taken away from the center 
or axis. Moreover, the metal must be worked 
against the form, at first, at the center until it is 
firmly in contact with the form-block. This is very 
important. If spinning is successfully done, it will 
be largely due to first establishing a firm contact be- 
tween the metal and its form-block at the center. 
Gradually this contact surface is increased as the 
tool continues to work outward. 

It has been assumed that the dish form will be 
spun with comparative ease. This will probably be 
true if the bulging, just referred to, and buckling do 
not together or separately hinder. As has been ex- 
plained, bulging is the result of over-compression 
with the tool. Buckling is one phase of bulging. 
While the tool is working toward the center, bulg- 
ing may take place. While the tool is working out- 
ward and when it is pressing against metal that is 
not in contact with the form-block but is simply be- 
ing supported by the stick in the left hand, buckling 
is a common danger. The metal begins to feel 
rough under the tool and the tool will seem to jump 
from point to point. Upon investigation it will be 
found that the metal is folding or lapping in places. 
If it is at once annealed, the difficulty may be over- 
come, but otherwise it will continue and finally the 
metal will shatter, ruining the piece. There are two 
reasons for this. The first one : the stick is not kept 
directly opposite the tool point, and, in addition to 
this, is probably not pressed firmly enough against 
it. It may be true, also, that pressure is being ap- 



METAL SPINNING 47 

plied too far from the contact surface, yet this in 
large work must be true, else the outer portion of 
the metal will tend to curl back toward the tailstock 
and the metal will take the form of a sombrero hat. 
The second reason: hard metal. With amateurs 
this is often the principal cause of buckling. The 
only remedy is to anneal the metal as previously 
mentioned. 

It must be remembered that lubrication in spin- 
ning is quite as essential as the use of oil in machine 




I 



Two Popular Forms 

bearings. Soap or tallow applied often and in small 
quantities is much better, as experience will prove, 
to both metal and workman than large quantities 
applied less frequently. 

The speed of a lathe used for dish spinning de- 
pends somewhat upon the diameter of the disc 
when spinning is commenced. For disc diameters 
less than 7 or 8 in. a speed of from 1500 to 1800 
r.p.m. is sufficient. For larger diameters lower 



48 



METAL SPINNING 



speeds are required. When the dish has finally 
been formed and smoothing and polishing are the 
only operations left, the speed may profitably be 
increased to 2000 r.p.m. or even more than this for 
small diameters. Too great a speed will, through 
centrifugal force, throw the metal away from the 
form-block. 




CHAPTER V 

HOW TO SPIN A DEEP DISH 

Under this head I shall treat forms which ap- 
proach the cylinder and require the use of two 
form-blocks (for beginners at least) instead of one. 
The illustration on page 42 shows forms of this 
character cups, toothpick and match holders, etc. 
Spinning metal into a cylindrical form involves a 
difficult operation that of turning the outer por- 
tion of the circular disc which is being spun, 
through an angle approaching 90 and consequently 
compressing very materially the metal at the outer 
portion of the disc. In addition to this there is the 
difficulty of turning the sharp corner between the 
bottom of the form and the cylindrical surface 
forming the sides. An experienced hand will do 
both of these things with apparent ease by using 
the tool and stick as described in Chapter III. 
However, as the metal is bent or turned through an 
angle approaching 90 the operator must spin in the 
air, as it is called. In other words, nothing sup- 
ports the metal from the time it leaves the circular 
disc shape until it reaches the finished form except 
the tool and the supporting stick ; the metal is there- 
fore spinning in the air. If one is proficient in the art 
of spinning in the air, only one form-block will be 
needed for deep forms as was the case with shallow 
forms. Few men, however, are capable of spinning 
large pieces in the air when the metal at the outer 
portion of the disc must be compressed consider- 
ably. Intermediate form-blocks are therefore used. 



50 METAL SPINNING 

To explain better deep dish spinning I shall refer 
to a specific problem which I have shown by line 
drawings on page 34, Fig. 11. A and B are vertical 
cross-sections through two form-blocks which in 
this case may be fastened on center screw face- 
plates, each form-block being turned and kept on a 
single faceplate until all spinning is done. A is the 
intermediate form-block and B the finished form- 
block for the cup illustrated at C, Fig. 11. The 
dotted line in A is a duplicate of the form B, so that 
one can easily estimate the relative amount of spin- 
ning which must be done on each block. It is sup- 
posed that the metal being spun will be annealed 
after it is taken from form-block A and before it is 
put on form-block B. 

In showing only one intermediate form-block the 
writer is taking it for granted that the instructions 
given in Chapter IV will enable one to spin the 
metal on each of the two form-blocks without diffi- 
culty. If this is not true as many intermediate 
form-blocks as desired may be prepared consistent 
with the number of annealings which the metal will 
stand. It is always necessary to do some spinning 
in the air, otherwise the supporting stick which is 
held in the left hand would not be needed. This 
supporting stick, however, is in reality, only a 
makeshift form-block, and when the intermediate 
form-blocks are many, the process of supporting 
the metal by the use of the supporting stick is not 
called spinning in the air. 

It will be noticed that the dotted outline and the 
solid outline in A coincide at the right, not only on 
the line which pictures the end of the chuck, but 
also for % in. or % in. on the cylindrical surface. 



METAL SPINNING 51 

The object of the preliminary form-block and all 
intermediate form-blocks hereafter described is 
two-fold : first, to provide easy steps in the process 
of spinning; and. second, to give a contact surface 
when spinning is begun on succeeding form-blocks. 
The imagination, I believe, will easily lead one to 
appreciate the significance of the first of these ob- 
jects, but the second will be fully appreciated only 
when one has endeavored to spin some form similar 
to the one illustrated where a contact surface is not 
maintained throughout the spinning process. When 
the metal is taken from form A and put on form B, 
a portion of the cup is in its final shape and is firmly 
seated on the form-block at the end, making the 
work secure. 

The method of bringing the metal down to the 
block B after the block A has been produced is 
somewhat different than has heretofore been de- 
scribed. In obtaining form A the tool has been 
moved outward, with possibly a few exceptional 
strokes of the tool, toward the center. This has 
prevented bulging and has gradually drawn the 
metal into the desired shape without necessarily 
thinning it. If this same manipulation of the tool 
is continued when the intermediate block B is used 
the metal will be thinned until it will be liable to 
crack before the form-block is reached by the metal. 
Furthermore, it will buckle very probably, not be- 
cause of its hardening or its being worked too far 
from the contact surface, but because it is thin and 
consequently weak. For these reasons the tool is 
moved toward the axis when using form-block B. 
This compresses the metal, as previously described, 
decreasing its circular measurements and at the 



52 METAL SPINNING 

same time thickening it. It will not bulge during 
this process because the base of the cup is firm 
against the chuck. It must not be supposed that 
the inward movement must be used to the ex- 
clusion of the outward one. I mean to infer that 
the former should predominate. By careful work 
and gradual pressure the metal will finally touch 
the form-block at all points. 

Mention has not been made thus far of the tools 
to be used, as it is believed enough was said in 
Chapter IV to enable the beginner to use his judg- 
ment in the selection of tools. My opinion is that 
the round-nose and lifting tool, if they are properly 
formed, can successfully do all dish and cup spin- 
ning of an ordinary character. For the purpose of 
smoothing, however, some tool with a flat surface, 
such as the tongue or planisher, will undoubtedly 
be used with more facility and possibly with better 
results. I would suggest the use of copper or 
aluminum for all work thus far described, if strength 
of material is an object and if the operator is an 
amateur of spinning work. However, white metal 
is more easily worked than copper and is the cus- 
tomary metal for the base in plated ware. Brass 
is rather too tough and hard, and zinc is too brittle 
for one to use in the experimental stage of spinning. 

If considerable difficulty is experienced in secur- 
ing the desired results, I offer the following as sug- 
gestive helps. First : Endeavor to spin a saucer 
of small diameter and of simple outline, or a cup 
whose sides make an angle of about 75 with the 
base, before attempting something more difficult. 



METAL SPINNING 



53 



Second : In cup spinning use three or even four 
form-blocks, if perseverance will not accomplish the 
desired result with two. 

The speed of the lathe for work coming in the 
class here considered can be a trifle higher than 
that given as average in a previous chapter. 




54 



METAL SPINNING 




CHAPTER VI 



HOW TO SPIN A VASE 

In this chapter we will consider all forms which 
may be called vases. In some cases the word vase 
form implies a neck or a top smaller in diameter 
than the bottom. It is this peculiarity which seems 
to make it necessary that the spinning of vases 
should be dealt with separately. 

The manipulation of the tools in this group or 
class of forms will be spoken of briefly as very few 
new operations in tool work are introduced. Usual- 
ly a greater number of tools are required to com- 
plete a vase form than are used for simpler objects; 
these will be mentioned later. 

The principal variation Irom the general method 
of work comes in making the form-blocks. Usually 
three form-blocks will be needed for a vase-form 
which has a neck smaller than its base, unless one 
is an adept at spinning in the air. As this book 
is supposed to be used by amateur workmen, as 
well as others, I shall consider that preliminary and 
intermediate form-blocks will be used in beginning 
work at least. We will consider a specific problem 
again in order to illustrate and describe to the best 
advantage detailed methods of spinning. Figure 12 
shows vertical cross-sectional drawings of a pre- 
liminary and intermediate chuck, and the end view 
and elevation of the final form-block used in spin- 
ning a vase-form represented at C in this same cut. 
In Fig. 13 also will be seen a vertical cross-section 



56 



METAL SPINNING 





METAL SPINNING 57 

view of a form-block showing the construction of 
a block or chuck for a vase with a small neck. 

Here (Fig. 12), as in Chapter V, A and B are 
simply used as easy steps in obtaining the form 
shown at C. It is only necessary, I believe, to call 
attention to the fact that the diameters shown at 1 
and 2, in A, B and C, and 3, in B and C, are the same. 
The object of this is to produce contact surfaces 
for each succeeding form-block. 

One is not advised to undertake the spinning of 
a vase-form before simpler forms have been tried. 
This is because the work as a whole is more difficult 
than it is in simpler pieces. There is a particular 
difficulty, too, which should be mentioned. The 
neck of the vase being smaller than its base the 
metal must be compressed to an unusual degree 
as it is drawn over toward the several form-blocks. 
After this compression comes a drawing-out process, 
the result of which is the neck of the vase. Such 
severe treatment of the metal is safe only in the 
hands of spinners of some experience. 

In order to draw the form-block out of the vase- 
form after it is spun, some kind of split-chuck must 
be used, such as is shown at C, or else the solid 
chuck must be burned and bored out of the finished 
article. As this last operation is much more difficult 
than one might at first suppose, and, also, as by this 
method of ridding the vase from its form the vase 
is liable to be damaged, it has become customary to 
devise some form of split-chuck with a key piece 
which, when withdrawn, will allow the remainder 
of the chuck parts to loosen, when they may be re- 
moved with ease. 

In preparing these split-chucks one should first 



58 METAL SPINNING 

carefully select a piece of dogwood or a very 
straight-grained piece of hard maple, and bore a 
hole, with the grain, through the block from end to 
end. It is desirable that this hole should taper 
slightly. This may be accomplished by first bor- 
ing a straight hole and then carefully gouging it 
to a taper. 

A better method of tapering the hole is to use a 
taper reamer after the straight hole is bored. The 
reamer will leave a hole that will be true and con- 
sequently an arbor will touch the stock at all points. 
If neither of these methods seems feasible, the 
straight, cylindrical hole may be made tapering by 
using a tapering, wooden spindle covered with sand- 
paper. When the hole has been properly prepared 
to receive the spindle, the two parts of the chuck 
should be put together and the desired form turned. 
This form or form-block, as we have called it, is 
next driven off of its arbor (the spindle) and split 
as illustrated in C, Fig. 12. The form-block is split 
so that all parts taper toward the center of the block 
except one, marked "1" in the illustration. This 
piece, the key piece, will be large at the center and 
small on the outside of the form-block. Besides 
being careful in turning and in splitting the chuck, 
one must use judgment in so proportioning all parts 
that the key piece may be first withdrawn through 
the hole which was bored for the arbor, and then 
others may be withdrawn without difficulty if they 
are not left too thick. When the chuck has finally 
been prepared as described, it is ready for use. The 
parts will be held together at the base by the metal, 
which has the same shape at the base of the vase 
as the last formed chuck. The parts are held to- 




Specimens of the Spinner's Finest Effects 



60 



METAL SPINNING 




METAL SPINNING 61 

gether at the top of the vase by some device similar 
to the one shown at 3, Fig. 12, or a similar device 
more clearly illustrated in Fig. 13. 

Probably the most difficult spinning to be done 
in the vase-form shown in Fig. 12 will be changing 
the form from A to B. Here the means of compres- 
sing the metal by spinning in the air will be em- 
ployed. Bulging ought not to be the result, if the 
metal fits tightly at the base of the vase. A con- 
siderable amount of compressing must be done, how- 
ever, to get the metal into the cylindrical form 
shown in B and one must use a great deal of care to 
prevent trouble in this operation. Instead of keep- 
ing the metal as thick as the original sheet one must 
compress it enough (in the vase-forms which have 
a neck) to allow it to be drawn out on chuck C, 
in making the concavity for the neck. This requires 
simply that the process of compression should be 
continued longer than usual. The neck is' formed 
by placing the tool point under the axis of revolu- 
tion and working from the larger diameters toward 
the smaller diameters after the cylindrical form 
spun on B is placed on block C. Attention is called 
to the fact that the diameters at 3 in B and C are 
the same, and also the same as the diameter at 2. 
Another method for forming the neck is to use such a 
tool as the lifter; it is pushed toward the axis and 
worked downward from each side toward the small 
diameter. 

Should a form be desired with a substantial roll 
at the top, as in Fig. 14, an additional chuck may 
be required which will allow the whole vase, with 
the exception of the top, to be admitted, as shown 
in Fig. 14 at the bottom of the sheet. In this kind 



62 METAL SPINNING 

of a vase-form, in which the base is larger than the 
top, the chuck used in making the rolled neck must 
be split in halves or quarters in order to allow the 
chuck to be withdrawn from the finished vase-form. 

I have only indicated the methods employed by 
old spinners in obtaining double-curve vase-forms. 
There is great opportunity for original devices and 
methods in spinning any article, but in this class 
of work perhaps there is more chance for the de- 
velopment of individuality on the part of the work- 
man than in work such as has been described in 
previous chapters. 

Little more need be said concerning the use of 
tools, annealing, etc. than has already been said. 
Annealing must take place whenever necessary, but 
workmen should be proficient enough in spinning, 
when undertaking a difficult form, to require the 
minimum number of annealings for a particular 
piece of work. The tools used for any form should 
be selected with reference to their size and shape. 
As a rule the round-nose is considered the general 
tool. The knob raiser is the tool used particularly 
for lifting or raising in shallow portions of the form 
or in grooves. The planisher or the tongue is a 
satisfactory tool for smoothing straight, conical or 
cvlindrical surfaces. 



CHAPTER VII 

HOW TO SPIN SOME UNCLASSIFIED 
FORMS 

^'hatever a man's occupation may be he is at 
any time liable to be confronted with new problems. 
The school cannot teach all, even though it strives 
to lay the foundation for all. I have attempted in 
these chapters to give the foundation for all metal 
spinning as it is now practised. In this chapter I 
shall speak only of a few operations which may add 
to the information thus far given, and, should the 
reader spin other forms than those previously de- 
scribed, this chapter may be helpful. 

Spinning in the air has been referred to as the 
control of the metal when it is spinning between 
the tool in the right hand and a stick in the left. 
It is true that this is one kind of spinning in the air, 
but there is another kind that I wish to describe. 
In general, air spinning or spinning in the air is any 
spinning operation in which the desired form is ob- 
tained without the use of a form-block or chuck. 
Usually this kind of spinning requires great skill, 
but there are operations in this class which, with 
little practice, are performed with comparative ease. 
The illustration, Fig. 15, shows a piece of spindle 
spinning which has an irregular shape in the center 
where the diameters are smaller than those at the 
ends of the spindle. If all of this should be spun 
over a solid form, it would be impossible to with- 
draw the form when spinning was completed. It 
is also practically impossible to make a workable 



64 



METAL SPINNING 



in 






METAL SPINNING 65 

split form, due to the small diameters. Either one 
of the following two methods seems possible. One, 
that of spinning over a solid form which will, in the 
end, be burned or bored out, or, the other, that of 
spinning the metal without the use of a definite 
form. The former of these two methods is slow, 
and dangerous to the article spun. The latter is 
quickly accomplished and, when the spinning opera- 
tions are completed, additional work is unnecessary. 

Figure 15 shows two chucks used in forming the 
spindle. A is solid and is the form first used. B 
shows the second form used. It will be noticed 
that the shape of the chuck A permits of its removal 
from the spun article without difficulty. The shape 
of the finished piece, however, would interfere in 
such a removal, consequently some chuck is devised 
which will hold the metal spindle at each end and 
may be withdrawn when the central part of the 
spindle is finished. 

The part of the spindle between points 1 and 2 
is spun in the air. The tool is carefully pressed 
against the metal as it revolves, working from the 
large diameter which was formed on chuck A to 
the small diameters as indicated in the drawing. 
Here one can use such tools as the groover and 
tongue to good advantage. This illustration of spin- 
ning in the air will serve to explain the meaning 
of this expression and to show the possibilities in 
this direction. The scope of this particular kind 
of spinning can only be realized as one practises and 
strives to be ingenious in the invention of means 
whereby difficult forms may be produced. 

Thus far, with the exception of a single mention 
of a means of producing a large roll at the top of 



66 



METAL SPINNING 




METAL SPINNING 67 

a vase, all faceplate chucks described have been 
convex toward the faceplate. Some work requires 
a chuck which is concave toward the head of the 
lathe. Usually, when this is true, a preliminary 
chuck of the first kind is used to spin the base of 
the article desired and also to spin the metal above 
the base into a cylindrical shape. 

An example of work which will require both the 
convex and concave chucks is given in a hanging 
flower pot, Fig. 16. Most plants which may be 
kept in a hanging pot require considerable water 
and many of them require water continually stand- 
ing in the pot. At the same time earth ventilation 
is necessary. The spun pot illustrated on page 66 
is designed to fill these needs, and serves in this 
instance as a good example for a problem in spin- 
ning. 

The style of chuck ordinarily used for spinning 
cups will first be employed. The end of this form 
is flat and as the metal which will form the bottom 
of the pot will be concave, as illustrated, consider- 
able metal should be compressed near the axis of 
revolution for this purpose. Usually the first move- 
ment of the tool is outward from the center. This 
operation produces a contact surface and thins the. 
metal slightly. To compress the metal we must 
move the tool toward the center, but this will pos- 
sibly loosen the metal at the base and may also 
bulge it. These risks must be taken, however, and 
can be overcome by using both the outward and 
inward motions of the tool in successive strokes. 
The outward strokes will tend to keep the metal in 
its proper shape, while the inward strokes, if suffi- 
cient force is exerted, will compress the metal slight- 



68 



METAL SPINNING 




METAL SPINNING 69 

ly with each movement. When sufficient compres- 
sion has been obtained, the metal may be drawn 
over the chuck as described in previous chapters. 

The chuck with the concave bottom is used when 
the metal has been spun to the first form. The 
basket as it comes from chuck 1 has a large contact 
surface prepared for chuck 2, and if the contact is 
a good one, the center may here be dispensed with 
and the rest may be placed at right angles to the 
lathe-bed and directly in front of the work after the 
neck of the basket is spun. The raising-up tool, 
round-nose or knob raiser may be employed in con- 
caving the bottom by gradually working the tool 
outward, principally, and inward but slightly. The 
hole in the bottom can be drilled through while the 
work is still on the chuck, by placing a drill in a 
tailstock chuck as in regular machine-shop work. 
Probably the hole may be as satisfactorily cut by 
using the point of a diamond point hand-tool just 
before removing the basket from this chuck or form- 
block, which must be split as in Fig. 14, as by 
drilling. 

I believe we have considered all the necessary 
operations for spinning single pieces of metal. I 
shall attempt to give the reader an idea of the 
method of spinning two pieces of metal together. 
No better example, I believe, can be given than 
the hollow sphere. Illustrations of this are shown in 
Fig. 17. 

Two hemispheres are separately spun as illus- 
trated at A. In fact each should be greater in depth 
than in diameter to allow for the inward and out- 
ward turns of the edges shown at B. After the two 
pieces have come from the convex chuck, each is 



70 



METAL SPINNING 




METAL SPINNING 71 

put into a concave chuck which permits the hemi- 
spheres to set inside with the amount, which was 
left for the turn, projecting. The outward turn is 
easily made by gently pressing the round-nose or 
the back of the tongue tool against the edge of the 
metal on the inside of the hemisphere and allowing 
the tool to follow the metal as it rolls outward. 
After the roll has been made it may be pressed 
down to the regular shape and thickness. 

The half which has the edge turned inward is 
placed in the same chuck which was used for the 
first half and the turn accomplished in practically 
the same manner, except that the tool is pressed 
against the metal from the outside and follows it 
as it turns inward. When the turn has been com- 
pleted to the satisfaction of the workman, he presses 
the end of the grooving tool or round-nose against 
the inside of the hemisphere just at the end of the 
turn and makes the slight roll shown at B. 
This forms a slight shoulder against which the 
second half of the sphere presses when the two are 
formed together. Either the inward or outward 
rolled edge may be formed by the use of the spin- 
ners' pliers which are shown in Fig. 18. If these 
are employed instead of the ordinary spinning tools, 
they grasp the edge of the metal as it revolves and 
the workman throws the handle in or out, depending 
upon the formation of the inward or outward turn. 
It is best to complete last the half having the in- 
ward roll. This half should remain in the chuck 
when the two halves are formed together. 

Leaving the first half in its place in the chuck, 
the second half is pressed into it until the two rolls 
come together, when the tail center is drawn up 



72 METAL SPINNING 

and presses the two halves firmly together. A firm 
but slight pressure with the end of the groover spins 
the two halves together. If the sphere is desired 
perfectly air or water tight, a bit of solder may be 
run into the seam. 

The method of making the sphere just described 
is by no means a simple one nor is it one that can 
be followed with success by all workmen. C in 
Fig. 17 shows another means of reaching the same 
results in an easier way, but here an extra strip is 
soldered on the inside of one of the hemispheres 
which does not permit of spinning operations alone 
being used in the production of the finished article. 
Such a problem as this is more practically done by 
pressing machines than by spinning methods as 
herein described. 

In closing this chapter, and as a last word, I wish 
to express the hope that many will undertake this 
almost entrancing form of cold metal work. It de- 
serves a place among the crafts, and, I believe, is 
worthy of consideration from a commercial stand- 
point. 





Examples in Copper 



Contents 

Aluminum .... 37 

Brass 36 

Copper 32 

Dish, Deep, How to Spin 49 

Dish, Shallow, How to Spin .... 39 

Lathe and Its Parts 11 

Metal, Preparation for Spinning ... 31 

Metal, White 35 

Preparation of Metal for Spinning ... 3 1 

Tools. . . 21 

Unclassified Forms, How to Spin ... 63 

Vase, How to Spin 55 

White Metal 35 

Zinc . 37 



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